1. Technical Field
The present invention relates generally to interconnection networks for computing systems. More particularly, this invention relates to optical interconnection networks with bidirectional optical switching.
2. Discussion of Related Art
Large data centers with hundreds or thousands of nodes require scalable and high-radix switch fabrics. Electrical switch chip port count is limited by pin density, for example, to less than about 150 ports/chip. Multistage electrical network fabrics can achieve higher port counts, but suffer from high power consumption, increased latency, congestion, and high cost. Typical multistage topologies (e.g. Clos, Benes, Spanke . . . ) achieve higher port counts than the number possible with multi stage topology. These multistage technologies may use non-blocking port-count doubling (e.g., to 2n×2n) and require at least 3 n×n switches (Clos-topology), with some methods requiring 4 n×n switches (Benes-topology). While an optical switch unit can be built with higher port counts (e.g. using 3D MEMS mirror technology), the applications of the optical switch have been limited.
Therefore, a need exists for a bidirectional optical switch for various applications.